You will be fine. See the doctor as scheduled. When drinking are you getting rowdy? Water blisters are usually caused by things like rope burns or working manual labor when you are not used to it.
We do eat some strange stuff when we are drinkin don't we? haha Yes I think that your body is retaining water because of the alcohol in part but it could be more than that. It could be your heart too. You don't say how old you are or just how much or how long you have been drinking, but our bodies have a way of protecting themselves against the things we do to them. See your doc and find out if you could use a water pill or what. I am not trying to scare you with the heart reference but the possibility is there so I mention it anyway. Be careful and take care.
Oh and don't forget to drink water water water so your body doesn't get tricked like that. Take good care of your body and it will take good care of you. ;)